- Cut up the soap: Using a knife on a protected surface, cut all of the soap ends into small pieces. Shred and scrape as small as possible. Place all of the cut soap into microwave-safe glass or cup. Push the soap down so that it is snug in the cup. Fill the cup with enough water to reach the same height as the soap in the cup. Be careful not to add too much water – this will make it take longer to dry later.
- Microwave: Place the cup in the microwave on top of a plate or napkin to catch any overflow. Microwave for about 30 seconds, watching carefully for any water to boil over. Stop the microwave as soon as the water-soap mixture rises to the top of the cup.
- Press into mold: Pour the heated mixture into a mold for your soap. Silicone cupcake molds or a disposable cup work great. Using the back of a spoon or a small bottle, press the soap down in the mold.
- Dry: Let the soap sit for about a week until all of the water evaporates and the soap is dry. Pop out of the mold, and you have a new bar of soap!
Adapted from: http://www.instructables.com/id/Reuse-Your-Old-Soap/
Photos by Susan O'Donnell